Well, if like me, you'll start out with good intentions and end up grabbing the next one you see!
Try to stick to private parties. These cars show up at dealer auctions all the time and they are in rough shape. Dealers clean them up (or don't) and turn around and really oversell them. I looked at a Black 90 5speed at a dealer. Hadn't been washed,rear bumper cover had been spray painted black. Car had 80k miles, the radio was ripped out of it, the shift lever was missing the knob, the drivers seat plastic by the controls was smashed. He wanted 5K for it. I didn't even bother to open the hood.
The key to finding a good SC is to have patience. I didn't have much patience, but I got lucky and found a good private owner car. The owner had replaced his 89 with a 92or 93. So you can get lucky. Watch the local papers like a hawk. And don't hesitate to check the buy/sell boards here.
General Used Car rules:
If it's got over 75K expect to replace:
Alternator
Water Pump
P/S pump
A/C compressor
If you don't have to consider yourself lucky. I'm lucky.
If it's a 5speed and the clutch has never been replaced, expect to replace it if you are over 100K miles.
Watch out for salvage vehicles. You can get some good deals, or you can get burned. 89-92 cars are turning up as salvage a-lot as insurance companies seem to regularly total them. Then the surface items are fixed, a check engine light is ignored, and you don't know what you have.
The cheaper and older SC's are going to be the ones that need more work and cost more in the end. 5Speeds are more rare, especially in later model years. Thus they fetch a slightly higher price than Autos.